JPH0375730B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (1) Industrial Application Field The present invention provides a switching mechanism capable of switching the opening/closing operation mode of an intake valve or an exhaust valve into a plurality of modes according to a change in hydraulic pressure; A valve train for an internal combustion engine, comprising a control valve provided between the switching mechanism and a hydraulic pressure supply source for switching, and a control means connected to the control valve for controlling the operation of the control valve according to the operating state of the engine. Regarding a control device.

(2) Conventional technology Conventionally, such a device is disclosed in, for example, Japanese Patent Application Laid-Open No.
It is publicly known from Publication No. 19911 and the like.

(3) Problems to be Solved by the Invention In the conventional system described above, low oil pressure and high oil pressure are switched and supplied to the switching mechanism, and when the oil pressure is low, the valve opening lift amount and opening angle of the intake valve or exhaust valve are changed to the high oil pressure. The oil pressure supplied to the switching mechanism is lowered when the engine rotates at low speeds. However, if the engine continues to rotate at high speeds without the switching mechanism not switching due to some kind of failure, the valve train system may fail, and problems such as the engine's output not increasing will occur.

In view of such circumstances, the first object of the present invention is to
An object of the present invention is to provide a valve train control device for an internal combustion engine that detects that the switching operation of a switching mechanism does not correspond to a change in engine operating conditions.

A second object of the present invention is to provide a valve train for an internal combustion engine that achieves the first object and is capable of avoiding an abnormal state when the abnormal state is detected.

B. Structure of the Invention (1) Means for Solving the Problems According to the first invention, the control means is connected to an oil pressure detector that detects the oil pressure supplied to the switching mechanism, and the control means: The switching state of the switching mechanism corresponding to the oil pressure detected by the oil pressure detector and the switching state of the switching mechanism corresponding to the signal that controls the operation of the control valve are checked to see if they correspond to each other. configured to detect a condition.

According to the second aspect of the invention, in addition to the configuration of the first aspect, the control means is configured to output a signal for avoiding an abnormal state.

(2) Effect According to the configuration of the first invention, it is possible to detect that the desired hydraulic pressure is not being supplied to the switching mechanism due to an abnormality in the electrical system or the hydraulic system, and it is possible to detect an abnormal state.

Further, according to the configuration of the second invention, when an abnormal state is detected, it is possible to deal with the abnormal state, thereby avoiding problems such as failure of the valve train or failure of output to rise to a desired value. It becomes possible to do so.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. First, in FIGS. 1 and 2, a pair of intake valves 1, 1 provided in the engine body E are The first cam is divided into a low-speed cam 4, a high-speed cam 5, and a low-speed cam 4, which are integrally provided on the camshaft 2 which is rotationally driven at a reduction ratio of 1/2, and a rocker shaft 6 parallel to the camshaft 2. 2nd and 3rd rocker arm 7, 8, 9
and the switching mechanism 10 provided between each rocker arm 7 to 9 to open and close the locker arm.

The camshaft 2 is rotatably disposed above the engine body E, the low-speed cams 4 are integrated into the camshaft 2 at positions corresponding to both the intake valves 1, 1, and the high-speed cam 5 is integrated with the camshaft 2 at positions corresponding to both the intake valves 1, 1. It is integrated into the camshaft 2 between the low speed cams 4, 4. Both low-speed cams 4, 4 each have a high portion 4a having a relatively small amount of protrusion along the radial direction of the camshaft 2, and a base circular portion 4b. Further, the high-speed cam 5 has a protrusion amount along the radial direction of the camshaft 2 that is equal to the height of the high portion 4.
It has a high part 5a which is larger than 4a and has a center angle range wider than that of the high part 4a, and a base circular part 5b.

The rocker shaft 6 is fixedly arranged below the camshaft 2. This locker shaft 6 includes a first locker arm 7 that is interlocked and connected to one intake valve 1, a third locker arm 9 that is interlocked and connected to the other intake valve 1, and a locker arm 9 that is connected to the other intake valve 1. The second rocker arm 8 located in
and are divided into adjacent districts. Further, a cam slipper 11 that slides on the low-speed cam 4 is provided on the top of the first rocker arm 7, a cam slipper 12 that slides on the high-speed cam 5 is provided on the top of the second rocker arm 8, and a cam slipper 12 that slides on the high-speed cam 5 is provided on the top of the third rocker arm 9. is a cam slipper 13 that comes into sliding contact with the low-speed cam 4
is provided.

On the other hand, a flange 14 is provided on the upper part of both the intake valves 1, 1, and a valve spring 15 is interposed between the flange 14 and the engine body E. 1 is biased toward the valve closing direction, that is, upward. Furthermore, tappet screws 16 that can come into contact with the upper end of the intake valve 1 are screwed into the tips of the first and third rocker arms 7 and 9 so as to be movable forward and backward.

Referring also to FIG. 3, the second rocker arm 8
is slightly extended from the lock shaft 6 toward both intake valves 1, 1, and this second lock shaft arm 8
is a spring biasing means 19 provided between the engine body E
is elastically biased in the direction of sliding contact with the high-speed cam 5.

The spring biasing means 19 includes a bottomed cylindrical lifter 20 whose closed end is in contact with the second rocker arm 8, and a lifter spring 21 interposed between the lifter 20 and the engine body E. is slid into a bottomed hole 22 bored in the engine body E.

In FIG. 4, a switching mechanism 10 is provided between each rocker arm 7 to 9, which can switch between connecting and disconnecting them.

The switching mechanism 10 includes a first switching pin 23 that can connect the third and second rocker arms 9 and 8;
and a second switching pin 24 capable of connecting the first rocker arms 8 and 7; and a first and second switching pin 24.
a third switching pin 25 that restricts movement of 3 and 24;
A return spring 26 is provided that urges each of the switching pins 23 to 25 toward the connection release side.

A bottomed guide hole 27 parallel to the rocker shaft 6 is bored in the third rocker arm 9 with its open end facing the second rocker arm 8, and the first switching pin 23 is slid into the guide hole 27. , 1st
A hydraulic chamber 29 is defined between the switching pin 23 and the closed end of the guide hole 27. Also, the third Rotsuka arm 9
A communication passage 30 communicating with the hydraulic chamber 29 is bored in the rocker shaft 6, and a hydraulic pressure supply passage 31 is bored in the rocker shaft 6. Moreover, the communication path 30 and the hydraulic supply path 3
1 is always in communication with the third rocker arm 9 through a communication hole 32 formed in the side wall of the rocker shaft 6, regardless of the swinging state of the third rocker arm 9.

A guide hole 33 having the same diameter corresponding to the guide hole 27 is bored in the second rocker arm 8 in parallel with the rocker shaft 6 between both sides thereof, and the second switching pin 24 is slid into the guide hole 33. be done.

The first rocker arm 7 has a guide hole 34 with the same diameter and the same diameter as the guide hole 33, which is parallel to the rocker shaft 6 and whose open end is connected to the second rocker arm 8.
The third switching pin 25 is slid into the guide hole 34 . Moreover, the third switching pin 25
A shaft portion 36 coaxially connected to the guide hole 34 is movably inserted into a guide hole 37 formed at the closed end of the guide hole 34 . Further, the return spring 26 is interposed between the closed end of the guide hole 34 and the third switching pin 25 by surrounding the shaft portion 36, and the switching pins 23 to 25 that are in contact with each other are connected by the return spring 26. It is biased toward the release side, that is, toward the hydraulic chamber 29 side.

When the hydraulic pressure supplied to the hydraulic chamber 29 is set to a relatively low pressure, for example, when the hydraulic pressure in the hydraulic chamber 29 is released, each of the switching pins 23 to 25 is moved toward the disconnection side by the spring force of the return spring 26. In this state, the contact surfaces of the first and second switching pins 23, 24 are between the third and second rocker arms 9, 8, and the contact surfaces of the second and third switching pins 24, 25 are between the second and second rocker arms 9, 8. Located between 1st Rotska Arm 8 and 7,
Each rocker arm 7-9 is not connected. Furthermore, when high hydraulic pressure is supplied to the hydraulic chamber 29, each of the switching pins 23 to 25 moves in a direction away from the hydraulic chamber 29 against the spring force of the return spring 26, and the first switching pin 23 is inserted into the guide hole 33. The second switching pin 24 slides into the guide hole 34 and each rocker arm 7
~9 are concatenated.

The hydraulic pressure supply path 31 in the rock shaft 6 is connected to a hydraulic pump 42 as a hydraulic pressure supply source via a control valve 41 that switches between an open state and a closed state by energizing and demagnetizing a solenoid 40. When this control valve 41 opens, the hydraulic chamber 2 of the switching mechanism 10
9 is supplied with high hydraulic pressure, and when the valve is closed, the hydraulic pressure in the hydraulic chamber 29 is released.

The solenoid 40 can be switched between excitation and demagnetization by a control means 43 such as a computer, and this control means 43 controls when the rotation speed input from a rotation speed detector 44 that detects the engine rotation speed exceeds a set value. and the control valve 41 is opened. The control means 43 also includes a hydraulic chamber 29 of the switching mechanism 10.
A signal is input from a hydraulic pressure detector 45 attached to the rocker shaft 6 to detect the hydraulic pressure of the hydraulic pressure supply path 31 leading to the hydraulic pressure supply path 31 . This oil pressure detector 45 is, for example, a pressure switch, and as shown in FIG. 5, it outputs a high level signal when the oil pressure in the oil pressure supply path 31 is a high oil pressure, and outputs a low level signal when the oil pressure is a low oil pressure, for example, zero. Outputs a level signal. Furthermore, the control means 43 has a function of checking whether the signal for controlling the solenoid 40 and the signal from the oil pressure detector 45 correspond. That is, it determines whether a high-level signal is input from the oil pressure detector 45 when the solenoid 40 is energized, and whether a low-level signal is input from the oil pressure detector 45 when the solenoid 40 is demagnetized. The control means 43 verifies whether or not there is one. As a result of this verification, if the signal from the oil pressure detector 45 is at a low level when the solenoid 40 is supposed to be energized, the control means 43 will, for example, cut off the fuel to be supplied to the engine and also turn off the alarm as an alarm. If the signal from the oil pressure detector 45 is at a high level when the warning light 46 is turned on and the solenoid 40 is demagnetized, the control means 43
turns on the warning light 46.

Next, the operation of this embodiment will be explained with reference to FIG. 6. In the first step S1, the control means 43 determines whether the engine rotation speed detected by the rotation speed detector 44 is below a set value. Check the
When the engine speed is below the set value, a signal to demagnetize the solenoid 40 is output in the second step S2, and when the engine speed exceeds the set value, a signal to energize the solenoid 40 is output in the third step S3. is output. When the solenoid 40 is demagnetized, the control valve 41 closes and the hydraulic pressure in the hydraulic chamber 29 is released, and each rocker arm 7 to 9 is in a disconnected state, and the intake valves 1, 1 are connected to the low speed cam 4,
According to the shape of 4, the opening/closing operation is performed while showing the profile shown by curve A in FIG. Also solenoid 4
0 is excited, the control valve 40 opens and the hydraulic chamber 29
As high oil pressure is supplied to the rocker arms 7 to 9, the intake valves 1 and 1 are connected to the high-speed cam 5.
The opening/closing operation is performed while showing the profile shown by curve B in FIG. 7 depending on the shape.

In the fourth step S4 after outputting the signal for demagnetizing the solenoid 40, it is checked whether the signal from the oil pressure detector 45 is at a low level, and if it is at a high level, the fifth step is carried out.
In S5, it is checked whether the state in which the signal from the oil pressure detector 45 is at a high level has lasted for a certain period of time or more, taking into account expected operation delays due to the viscosity of the hydraulic oil, etc., and when it has continued for more than a certain period of time, At step S6, the warning light 46 is turned on. As a result, when the low-speed cams 4 and 4 are supposed to open and close the intake valves 1 and 1, the rocker arms 7 to 9 are connected, and therefore the intake valves 1 and 1 are opened and closed by the high-speed cam 5. It is possible to detect and warn of abnormal conditions being activated.

Also, after outputting the signal for exciting the solenoid 40 in the third step S3, the seventh step S7
Then, it is checked whether the signal from the oil pressure detector 45 is at a high level or not, and when it is at a low level, it is checked at the eighth step S8 whether or not this state continues for a certain period of time or not, and the above-mentioned operation delay, etc. If the warning light persists for a certain period of time or more, which is set in consideration of 46 is lit.

In this way, the control means 43 detects that the operation mode of the intake valves 1, 1 has become abnormal due to a failure in the electrical system or hydraulic system of the valve train, and lights up the warning light 46 or It is possible to take measures to avoid the abnormal state by detecting an engine speed that is set to a value lower than the normal overspeed prevention setting speed during an abnormal situation and cutting off the fuel supply. can.

In the above embodiment, the operation of the switching mechanism 10 is controlled by the engine speed, but as shown by the chain line in FIG. 47 and a detector 48 for detecting the engine temperature are connected, and the switching mechanism 1
The operation of 0 may be controlled.

Furthermore, the present invention can be applied not only to a valve operating system for the intake valves 1, 1, but also to a valve operating system for exhaust valves.

C. Effects of the Invention As described above, according to the first invention, the control means is connected to the oil pressure detector that detects the oil pressure supplied to the switching mechanism, and the control means is connected to the oil pressure detector that detects the oil pressure supplied to the switching mechanism. The system is configured to detect an abnormal state by checking whether or not the switching operation state of the switching mechanism corresponding to the oil pressure and the switching operation state of the switching mechanism corresponding to the signal controlling the operation of the control valve correspond to each other. Because
It is possible to immediately detect an abnormal state in which the operation of the intake valve or exhaust valve does not follow instructions from the control means due to an abnormality in the electrical system or hydraulic system.
It becomes possible to take measures against this.

According to the second aspect of the invention, in addition to the configuration of the first aspect, the control means is configured to output a signal for avoiding the abnormal condition when an abnormal condition is detected. In addition to the effects of the invention, measures can be taken to avoid abnormal conditions, and failures in the valve train system can be prevented.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a plan view of a valve train, and FIG.
A line sectional view, Figure 3 is a - line sectional view of Figure 1,
Fig. 4 is a cross-sectional view taken along the - line in Fig. 2, Fig. 5 is an output signal characteristic diagram of the oil pressure detector, Fig. 6 is a flowchart showing the control procedure of the control means, and Fig. 7 is a valve opening lift of the intake valve. It is a figure showing a curve. DESCRIPTION OF SYMBOLS 1...Intake valve, 10...Switching mechanism, 41...Control valve, 42...Hydraulic pump as a hydraulic pressure supply source,
43... Control means, 45... Oil pressure detector, 46...
...warning light as an alarm.

Claims (1)

[Scope of Claims] 1. A switching mechanism capable of switching the opening/closing operation mode of an intake valve or an exhaust valve to a plurality of modes according to switching of hydraulic pressure, and a control provided between the switching mechanism and a hydraulic pressure supply source to switch the hydraulic pressure. In a valve control device for an internal combustion engine, which includes a valve and a control means connected to the control valve to control the operation of the control valve according to the operating state of the engine, the control means includes a hydraulic pressure supplied to the switching mechanism. An oil pressure detector is connected to the control means, and the control means controls the switching operation state of the switching mechanism corresponding to the oil pressure detected by the oil pressure detector and the switching operation state of the switching mechanism corresponding to the signal controlling the operation of the control valve. 1. A valve control device for an internal combustion engine, characterized in that the valve control device for an internal combustion engine is configured to detect an abnormal state by comparing whether or not the two correspond to each other. 2. The control means is configured to determine an abnormal state when the switching operation state of the switching mechanism corresponding to the oil pressure and the switching operation state of the switching mechanism corresponding to the signal are different for a certain period of time. A valve control device for an internal combustion engine according to claim 1. 3. A switching mechanism capable of switching the opening/closing operation mode of the intake valve or exhaust valve to a plurality of modes according to the switching of the hydraulic pressure, a control valve provided between the switching mechanism and the hydraulic pressure supply source for switching the hydraulic pressure, and a control valve that controls the operation of the engine. In a valve train control device for an internal combustion engine, the control means includes a control means connected to the control valve to control the operation of the control valve according to a state, and the control means includes an oil pressure detector that detects oil pressure supplied to the switching mechanism. is connected to the control means, and the control means is arranged so that the switching operation state of the switching mechanism corresponding to the oil pressure detected by the oil pressure detector and the switching operation state of the switching mechanism corresponding to the signal controlling the operation of the control valve correspond to each other. 1. A valve train control device for an internal combustion engine, characterized in that it is configured to detect an abnormal state by verifying whether or not the abnormal state is present, and to output a signal for avoiding the abnormal state. 4. The valve control device for an internal combustion engine according to claim 3, wherein the control means is configured to activate an alarm in response to detection of an abnormal condition. 5. The valve train for an internal combustion engine according to claim 3 or 4, wherein the control means is configured to cut off fuel supply to the engine in a predetermined operating state upon detection of an abnormal state. Control device.